Masafumi Kanetomo

Ultrashallow p‐type layer formation by rapid vapor‐phase doping using a lamp annealing apparatus

Ultrashallow p‐type layers below 30 nm were formed by a rapid vapor‐phase doping involving a lamp annealing system. A new one‐wafer‐type apparatus with tungsten lamps has been developed for use in this process. Temperatures at five different points on a 4‐in. wafer are in situ monitored by infrared radiative thermometers with optical fibers to maintain a uniform temperature profile across the wafer. By using hydrogen and B2H6 gas, an ultrashallow boron‐doped layer of below 30 nm with the surface boron concentration of 5.8×1019 cm−3 was formed after 10 s of 900 °C annealing with a B2H6 flow rate of 100 ml/min.

Spatially uniform lead perovskite thin films formed by MOCVD

Abstract To deposit PZT (Pb(Zr,Ti)O3) thin films on Pt films sputtered on thermally oxidized silicon wafers, we used Pb(thd)2, Zr(thd)4, and Ti(iOC3H7)4 as metal-organic chemical vapor deposition sources. The good composition control resulting form the use of Zr(thd)4 provided in-depth uniformity near the interface between Pt and deposited PZT. This uniformity was revealed by TEM observations and in-depth composition analysis using EDX with subnanometer probing radius. PZT films 80 nm thick had a leakage current of 2 × 10−7A/cm2 when the applied voltage was 1.5 V, and equivalent to a SiO2 thickness of 0.4 nm. The variation of composition and thickness over a 4″ wafer was about 1%. This surface uniformity achieved by optimizing the source supply and pumping system, results in the electrical uniform PZT thin films required for fabricating large-scale memory devices.